[nem-bug] [Nemerle 0000626]: Quoted declaration of method override results in compile-time error

[feedback at nemerle.org]

The following issue has been CLOSED
======================================================================
<http://nemerle.org/bugs/view.php?id=626> 
======================================================================
Reported By:                OysterDva
Assigned To:                nazgul
======================================================================
Project:                    Nemerle
Issue ID:                   626
Category:                   Compiler
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     closed
Resolution:                 fixed
Fixed in Version:           
======================================================================
Date Submitted:             02-25-2006 21:23 CET
Last Modified:              05-22-2006 18:05 CEST
======================================================================
Summary:                    Quoted declaration of method override results in
compile-time error
Description: 
Definition of method override using TypeBuilder.Define() and quoting fails
if base class contains generic method with the same name/signature and
value of template parameter type returned.

For example, imagine we have the following class declared in C# (as I
understand, it's impossible to declare such class in Nemerle):

namespace NS
{
  public class Test
  {
    virtual public object DoIt()
    {
      return null;
    }
    
    // Comment this method and error will go away
    static public T DoIt<T>()
    {
      return default(T);
    }
  }
}

Here we have two methods with name DoIt() and similar signatures - one is
virtual and another one is static method with generic type parameter.

Now look at the following macro code which creates type inherited from
Test:

macro Reproduce1()
{
  def ctx = Nemerle.Macros.ImplicitCTX();
  def t = ctx.Env.Define(<[ decl: public class TestInherit : NS.Test {}
]>);
  // This LOC causes an error to happen
  t.Define(<[ decl: override public DoIt() : object { null } ]>);
  t.Compile();
  <[ () ]>
}

When we're using this macro, the following compile-time error occurs:

"`override' specified on method TestInherit.DoIt() : System.Object, but
there is no method with this signature in parent to override"

If we'll comment static method in Test class then everything will be
compiled without any error.
======================================================================

----------------------------------------------------------------------
 nazgul - 02-25-06 21:29 
----------------------------------------------------------------------
Does it also happen when you are not using macros, but just define such
class manually?

----------------------------------------------------------------------
 OysterDva - 02-25-06 21:33 
----------------------------------------------------------------------
Yep - I've just checked it.

Btw, sorry if severity level will be too high - using mantis for the first
time :)

----------------------------------------------------------------------
 nazgul - 02-25-06 21:37 
----------------------------------------------------------------------
//t.cs
namespace NS
{
  public class Test
  {
    virtual public object DoIt()
    {
      return null;
    }
    
    // Comment this method and error will go away
    static public T DoIt<T>()
    {
      return default(T);
    }
  }
}


// t.n
public class TestInherit : NS.Test {
override public DoIt() : object { null }
}



Well, actually the problem is that your C# code should compile also under
Nemerle. It doesn't and it is a bug. The fact that compiler cannot
properly use such code is just a side effect of this bug.

----------------------------------------------------------------------
 nazgul - 05-01-06 12:23 
----------------------------------------------------------------------
Fixed on trunk (r6211).

Issue History
Date Modified  Username       Field                    Change              
======================================================================
02-25-06 21:23 OysterDva      New Issue                                    
02-25-06 21:23 OysterDva      File Added: src.txt                          
02-25-06 21:29 nazgul         Note Added: 0001106                          
02-25-06 21:33 OysterDva      Note Added: 0001107                          
02-25-06 21:37 nazgul         Note Added: 0001108                          
02-25-06 21:37 nazgul         Severity                 crash => minor      
02-25-06 21:37 nazgul         Category                 Compiler (parser/macros
engine) => Compiler
02-25-06 21:37 nazgul         Description Updated                          
02-25-06 21:37 nazgul         Additional Information Updated                    
05-01-06 12:23 nazgul         Status                   new => resolved     
05-01-06 12:23 nazgul         Resolution               open => fixed       
05-01-06 12:23 nazgul         Assigned To               => nazgul          
05-01-06 12:23 nazgul         Note Added: 0001215                          
05-01-06 12:23 nazgul         Description Updated                          
05-01-06 12:23 nazgul         Additional Information Updated                    
05-22-06 18:05 nazgul         Status                   resolved => closed  
======================================================================